Early on the morning of December 23, 1941—barely two weeks after Pearl Harbor—a Japanese submarine sank the S/S Montebello, an American oil tanker, off the central California coast. Seventy years later, the wreck of the Montebello still rests 900 feet beneath the sea just south of the Monterey Bay National Marine Sanctuary.
It’s one of the shipwrecks we’ve been investigating to make sure the oil still on the ship hasn’t leaked into the surrounding environment. No significant oil releases have been known to occur since it sank, and investigations in 1945, 1996, 2003, and 2010 have found the hull and cargo tanks to be intact. So the question remains, does the ship still carry the more than 3 million gallons of crude oil it was carrying when it went down?
For two and a half years, NOAA’s Office of Response and Restoration and Office of National Marine Sanctuaries have assisted the U.S. Coast Guard and the California Office of Spill Prevention and Response in evaluating the Montebello’s potential pollution threat.
Starting this month (Oct. 2011), NOAA will provide on-scene expertise in maritime history, biology, and scientific support to the Coast Guard as they assess the wreck’s condition with a remotely-operated vehicle (ROV), determine the ship’s corrosion status, the volume of oil still on board, and the oil’s physical and chemical properties. Once the evaluation is complete, the Coast Guard hopes to better understand the pollution threat posed by the Montebello and then determine what, if any, mitigation actions might be necessary.
Although navigation safety has improved dramatically in recent years, ships still sink, and the past century of commerce and warfare has left a legacy of thousands of sunken vessels along the U.S. coast. Some of these wrecks pose environmental threats because of hazardous cargoes, munitions, or bunker fuel oils left on board.
Unless they posed an immediate pollution threat or impeded navigation, most of these wrecks were left alone and largely forgotten unless they began to leak. Recent incidents, however, have heightened concerns about the potential environmental hazard posed by shipwrecks. In 2002, for example, the decaying wreck of S/S Jacob Luckenbach was identified as the source of mysterious, recurring oil spills that had killed thousands of seabirds and other marine life along California’s coast. My office joined with the U.S. Coast Guard and other agencies to remove the approximately 100,000 gallons of oil remaining in the wreck.
I’ve been working to prioritize which shipwrecks in U.S. waters pose the greatest potential threat from oil on board (hopefully, before they leak). Where are these wrecks? What condition are they in? Are they intact? Did all the oil leak out when they first sank, or could they still hold oil like the Luckenbach?
Researching shipwrecks is fascinating. Every ship has a story and that story is partially revealed through the accounts of the survivors, old newspaper stories, insurance investigations, accident records, and cargo reports. Salvage reports and survey records from NOAA charts add to the picture, but these old documents provide incomplete clues. Sometimes these silent wrecks at the bottom of the sea end up keeping some secrets down there with them.